Misfiring on the 1 and 3 cyclinder. need firing order to figure out what is causing it. Do you know firing order or what could cause misfire?

code p 0141 refers to heated oxygen sensor (HO2S) 2 bank 1--heater control--circuit malfunction===causes --wiring---HO2S--- ECM
code p 0144 refers to heated oxygen sensor(HO2S) 3 bank 1--high voltage ===causes wiring short to positive ---HO2S---ECM
also refers to oxygen sensor(O2S) 3 bank 1--high voltage ===causes wiring short to positive---O2S-- ECM
HO2S sensors are the units in the exhaust manifolds or before the cat converters
O2 sensors are after the cat converter
two completely different operations
use the special tool for sensors as the wires are easily damaged from the wrong tool use
as for misfiring you will get a P0300 (0300,0301,0302,0303 etc) depending on which cylinders are misfiring
when checking for misfiring the injectors , (blocked or not firing) are as important as plugs and wires
If the misfiring continues after sensor replacement , replace the ECM with a known good one as it is common to all fault codes and misfiring

Believe it or not the firing order is 1-2-3-4-5-6 The cylinder locations are 2-4-6 in front by radiator, and 1-3-5 against the firewall. If you have a misfire on a certain cyl. and you've replaced the plugs,wires and cap and rotor, you probably have a fuel injector that's dead or plugged,it's common on Quests. Figure out which cyl. is misfiring and unplug the fuel inj. conn. with the engine running and listen for a change in RPMs. If there is no change then replace the injector.

Intermittin Engine Stall
Engine No Start
Missfire
MISFIRE IN motor cylinder is more likely the cause to engine stall and hard start.
You will have to fix this problem first,
A misfire, most the time, is caused by, incorrect cylinder firing order (diagram at bottom). Or no or low cylinder compression
no or low compression is the result of A Vacumm leak.
If the timing chain was recently replaced, the valve cover had to be removed, the valve cover gasket could cause a huge vacumm leak which would effect some if not all 6 cylinders,

Symptoms
Lack/loss of power
Hard start
Engine hesitation

For Now
check firing order( coil pack to sparkplug)
check sparkplugs

NISSAN 3.5 V-6 FIRING ORDER
SPARK PLUG GAP 0.050''
SPARK PLUG TORQUE
COIL PACK LAYOUT


I hope this helps for now
If you have any questions, you can email or post back
[email protected]

This page should help
2005 Land Rover Freelander SE V6 firing order Google Search

Did you take a compression test? If it fails, then you know it's in the engine. Possible broken valve spring.

p132+ an O2 sensor reading is high bank1,sensor1, p135=O2 Heater circuit is bad, bank1,sensor1.

P300= Random misfires, p301 misfire cylinder1.p302 misfire cylinder2

p420 Bank1 Catalytic converter efficiency failing

What this means is that the Bank1 O2 sensor is either bad or the wiring to it is defective. Check for heat burnthrough on wires. The misfires started randomly and now pinpoint to cylinders 1 and 2.

The Catalytic converter failing because the misfires are clogging it. This can self correct once the cylinders stop misfiring.

Which messed up first is where you start solving this. Replace the O2 sensor, it is fouled out on Bank1. The heater circuit(p135) just makes it work faster and has little effect once you are underway. But high resistence in the O2(p132) means it is coated and ineffective.

There is a problem with firing #1 and #2 sparkplug. Probably the cause for the Catalytic converter plugging. A cracked coil, plug wires, sparkplugs are some causes as well as dirty fuel injectors on those 2 cylinders.

It is a cause and effect situation where 1 part fails and damages another. You need to fix the source of the problem or you will repeat th damage.

OK, We'll cover the Diagnostic Test Codes (DTCs), starting with the standard definition set by SAE J2012 (Revised December 2007)
DTC P0171 "System Too Lean Bank 1"
DTC P0174 "System Too Lean Bank 2"
DTC P0301 "Cylinder 1 Misfire Detected"
DTC P0305 "Cylinder 5 Misfire Detected"
DTC P0316 "Engine Misfire Detected on Startup (First 1000 Revolutions)"

The "system lean" codes are pretty much telling you that there is way too much oxygen in the exhaust. There is too much oxygen on BOTH sides of the engine, and that is why you are getting codes for bank 1 and for bank 2. Bank 1 is the side where #1 cykinder is located and Bank 2 is the opposite side.

The misfire codes are pretty self-explanatory. #1 and # 5 cylinders are misfiring. The P0316 DTC is telling you that the misfire monitor is detecting a misfire as soon as the engine starts. This tells you that it is a very severe misfire and that the engine does not have to warm up and the car does not have to be driven to detect the misfire.

A misfire can be caused by many things it can be vacuum leaks, bad spark plugs, bad ignition cables, faulty ignition coils, fouled or malfunctioning injectors or injector circuits, blown head gasket, cracked cylinder head, burnt valves, etc.. etc..

However, look at the codes you have. Then look at the firing order for your engine. 2002 Mercury Sable is only equipped with a 3.0L 2V 6-cylinder engine.
The firing order is 1-4-2-5-3-6

Now if you take the firing order and split it in half, stack the two halves on top of each other, it looks like this:
1-4-2
5-3-6

When you look at the firing order this way, you can see that cylinders 1 an 5, 4 and 3, and 2 and 6, are "PAIRED" cylinders. They are exacly opposite in the firing order. Now, the cylinder only fires every second revolution of the crankshaft. With paired cylinders, one of the cylinders in the pair will fire on the first revolution and the other cylinder will fire on the second revolution.

Looking back at your codes, please note that the cylinders that are setting the misfire codes are paired cylinders.

Now the coil pack for your ignition is actually made up of three coils. Each coil fires a set of paired cylinders. If you look at the top of the coil, it will usually be marked with the cylinder numbers that each coil tower is supposed to connect to. The coil will look just like the firing order split and stacked as above.

With all of this said, I would say that it is VERY LIKELY that your misfire codes are being caused by a defective ignition coil.

The lean codes are a little different.

These are USUALLY caused by vacuum leaks which allow too much air into the engine that is not getting measured by the Mass Airflow (MAF) sensor and causes the engine to be getting too much air and not enough fuel (running lean).

I would take a good look at all of the vacuum hoses and lines. Ford is notorious for getting holes in the rubber parts that connect the PCV tubes.

If you do not find any obvious reasons for a vacuum leak, then you may want to fix the misfire codes, reset the computer memory, and drive the vehicle to see if the lean codes come back again. The misfires COULD be the cause of the lean codes. In a perfect world, this is not supposed to happen because the misfire monitors setting codes will not allow the oxygen sensor monitors to run and set lean codes. However, I HAVE seen cylinder misfires that have caused lean codes.

I hope this helps you to figure it out. Good luck!

assume still misfiring?
have u checked the fuel injector????

They are still looking for a cause because it isnt misfiring right now or because they cant find the cause of the stored misfire codes ?
If it is misfiring right now and they cant figure it out then perhaps you should find new mechanics !
I have seen a lot of bad coils on the PT.
Misfire is usually caused by spark plug wires first, spark plugs 2nd, and coil third.
If it isnt misfiring now, spray down the wires with water. If it misfires after that replace the spark plug wires and spark plugs and try again.
If it still misfires then the problem will likely be the coil.

Here you go...